A 64 year old man presents with progressive gait instability and numbness in both feet. He underwent total gastrectomy 3 years ago for gastric cancer. Examination shows decreased vibration and position sense in the lower extremities, spasticity, and a positive Romberg sign. Hemoglobin is 10.1 g/dL with MCV 112 fL. Which of the following is the most likely pathophysiologic mechanism?
- A)Copper deposition in the basal ganglia
- B)Compression of the cauda equina nerve roots
- C)Demyelination of dorsal columns and lateral corticospinal tractsGABARITO
- D)Ischemic necrosis of the mammillary bodies
- E)Autoimmune destruction of Schwann cells
Explicação
Demyelination of dorsal columns and lateral corticospinal tracts is correct. Vitamin B12 deficiency causes subacute combined degeneration, producing impaired vibration and proprioception with sensory ataxia plus corticospinal tract dysfunction causing spastici... Ver explicação completa e trilha adaptativa →